This invention relates to fastener driving devices and, more particularly, to fastener driving devices of the portable type having a nail placement device or nail positioning mechanism.
Fastener driving tools for driving fasteners such as nails are commonly used in industry and commerce. The fastener driving tools are power operated and may be pneumatically powered, electrically powered or combustion powered. The fasteners are generally supplied from a collated strip or stick of fasteners disposed in a magazine assembly coupled to a nosepiece portion of the fastener driving tool housing. Typically a fastener feeding device advances the fasteners through the feed track of the magazine assembly toward and into a drive track in the nosepiece portion of the fastener driving tool. In the case of pneumatically driven tools, the housing of the fastener driving tool comprises a handle reservoir to store compressed air, a cylinder within the housing, a piston within the cylinder, a driver connected to the piston, and a main valve to provide pressurized air to operate the piston.
Fastener driving tools usually include a trip assembly mounted on the nosepiece and operatively associated with a trigger mechanism to prevent the driver from being actuated when the nosepiece is not in contact with a workpiece. Contact trip assemblies are often sequentially associated with the trigger mechanism so that when the nosepiece is placed in contact with the workpiece, the trip assembly moves with respect to the tool frame and places the trigger mechanism in an active condition so that the driver can be actuated by movement of the trigger mechanism through its actuation stroke.
In some instances, fastener driving tools may also include a positioning mechanism or a nail placement device for positioning the tool relative to an opening in a workpiece, such as a metallic structure, to be fastened to another adjacent workpiece, such as a wooden structure.
Positioning or pointing mechanisms have already been used for aligning the nosepiece with respect to the opening in a workpiece so that a fastener (such as a nail) can be precisely driven through the opening. For example, U.S. Pat. No. 5,452,835 discusses a positioning mechanism for powered fastener-driving tool. The mechanism comprises a probe having a tapered end adapted to extend into the opening of the workpiece. The mechanism comprises a pivot for mounting the probe to an actuator operatively mounted to the nosepiece. The probe is mounted on the pivot so as to provide a pivotal movement of the probe relative to the actuator. When a nail is driven by the tool, the head of the nail engages a surface of the probe thus pivoting the probe from the opening as the tool recoils.
Another positioning mechanism found in the commerce is one sold under the tradename of xe2x80x9cTHE LOCATORxe2x80x9d manufactured by Range Bull Technologies. A perspective view of this positioning mechanism is shown in FIG. 9, and a cross-section view is shown in FIG. 10. Positioning mechanism 200 comprises a rigid structure 201 having an elongated bar-like portion 203 and an annular portion 205. The bar-like structure comprises opening 207 for fastening the positioning mechanism 200, with a screw or the like, on a contact trip mechanism (not shown) such that the positioning mechanism forms an extension of the contact trip mechanism. The nosepiece portion of the fastener driving tool comes in contact with the inside surface of the annular portion 205. The annular portion 205 includes an integral opening locating element 202. The opening locating element 202 is located at a lower extremity of the annular portion 205 in general alignment with the bar-like structure 203.
The opening locating element 202 has a half-conical shaped hole entering portion 209. Opening locating element 202 is integrally formed with the annular portion 205. Specifically, opening locating element 202 does not move relative to the bottom portion 204 of the annular portion 205, thus the opening locating element 202 does not move relative to the rigid structure 201 of the positioning mechanism 200. Positioning mechanism 200 also comprises nail pusher 206 pivotally connected to the rigid structure 201 and biased by biasing spring 208 such that the pointed end of a nail 210 is pushed against a tapered arcuate surface 211 of the hole entering portion 209. Nail pusher 206 has a rod-like shape extending from pivot point 212 to pointed end 214 which in turn is brought in contact with nail 210. As mentioned previously, the opening locator 202 forms an integral part of the annular portion 205. Therefore, opening locator 202 does not move relative to bottom portion 204 of positioning mechanism 200.
The prior art is limited in its performance. For example, due to the bulkiness of the opening locator in the positioning mechanism xe2x80x9cTHE LOCATORxe2x80x9d it is hard to see the opening locator 202 and locate an opening at the same time which may lead to jamming and/or missing the opening. Therefore, it is desirable to overcome these and other limitations thus allowing overall improved performance and reduced cost of the fastener tool.
In accordance with the principles of one aspect of the present invention, a fastener driving device comprises a frame structure presenting a handle portion constructed and arranged to be gripped by a user enabling the user to handle the device in portable fashion, a nosepiece structure operatively fixed with respect to said frame structure defining a fastener drive track, a fastener driving element movable through the drive track. The fastener driving device also includes a power operated fastener driving system carried by the frame structure constructed and arranged to move said fastener driving element through successive operating cycles each including a drive stroke and a return stroke and a magazine assembly carried by said frame structure having fixed structure defining a fastener feed track leading to the drive track and movable structure constructed and arranged to enable a package of fasteners to be loaded in said magazine assembly and fed along the feed track so that the leading fastener of the fastener package is moved into the drive track to be driven outwardly thereof into a workpiece during the drive stroke of the fastener driving element. The fastener driving device further includes an actuating mechanism constructed and arranged to actuate the power operated driving system including a manually actuatable trigger assembly and a contact trip assembly. The contact trip assembly comprising a trigger enabling portion and a movable assembly coupled to the trigger enabling portion, the contact trip assembly being constructed and arranged to be movable between an extended position and a retracted position whereby the trigger enabling portion enables the trigger mechanism to activate the fastener driving element when actuated by a user when said contact trip assembly is in the retracted position and disables the trigger mechanism when the contact trip assembly is not in the retracted position. The contact trip assembly is constructed and arranged to be biased toward the extended position and to be moved toward the retracted position when the movable assembly engages a workpiece by pressing the frame structure toward the workpiece, thereby moving the contact trip assembly with respect to the nosepiece.
The fastener driving device further comprises a positioning mechanism constructed and arranged to position the nosepiece structure into an opening in a first workpiece such that a fastener is driven through the opening to fasten the workpiece to a second workpiece. The positioning mechanism includes an opening locating structure movably connected to the movable assembly of the contact trip assembly and adapted to extend into the opening so as to align the nosepiece with respect to the opening. The opening locating structure is movable relative the movable assembly of the contact trip assembly between an extended position and a retracted position and biased toward the extended position by a first biasing spring to facilitate locating of the opening, and movable to the retracted position when the opening locating structure is pressed against the first workpiece. The positioning mechanism further includes a guiding structure movably connected to the nosepiece structure, the guiding structure being biased by a second spring to extend forwardly to guide the fastener in the driving track.
In one embodiment, the guiding structure is biased by the biasing spring such that when a fastener is introduced into the drive track the guiding structure forces a pointed end of said fastener to be proximate to the opening locating structure.
In one embodiment, the guiding structure is constructed and arranged to pivot around a pivot axis disposed at an extremity of said guiding structure. In another embodiment, the guiding structure is constructed and arranged to slide perpendicularly to a driving axis defined by the driving track in the nosepiece. In one embodiment, the guiding structure has an oblong-like shape. In an alternate embodiment, the guiding structure has an sector-like shape.
Another aspect of the invention is to provide a fastener driving device including among others an actuating mechanism including a trigger assembly constructed and arranged to be actuated by a manual movement and a contact trip assembly constructed and arranged to be actuated by a movement of the housing into a workpiece with said drive track at a fastener driving position with respect thereto. The actuating mechanism is constructed and arranged to actuate the power operated system in response to a predetermined actuation of the trigger assembly and the contact trip assembly. The contact trip assembly is constructed and arranged to be moved into engagement with a plied workpiece including a member having an opening therethrough and a substrate to which the member is to be attached by a fastener extended through the opening and into the substrate.
The contact trip assembly includes a trigger enabling structure movable with respect to the housing, and cooperating with the trigger assembly, an opening locating structure constructed and arranged to engage within the opening to initiate the actuation of the contact trip assembly after which during an initial contact trip actuating movement of the housing, the trigger enabling structure moves with the housing and with respect to the opening locating structure and a final movement of the housing to actuate the contact trip assembly. The housing is moved with respect to both the opening locating structure and the trigger enabling structure.
Other aspects of the present invention is to provide a device of the type describe above which is combined with other features hereafter described in detail.